At the time of delivery, 98% of Ugandan women on efavirenz maintained suppression of HIV to undetectable levels, compared with 86% of women who were being treated with the protease inhibitor combination of lopinavir/ritonavir (Kaletra) (P<0.001), reported Diane Havlir, MD, professor of medicine at the University of California San Francisco.

Among the 358 women who completed the study, two of their infants were HIV-positive. One child was infected in utero and another through breastfeeding. Both of those children were on the lopinavir treatment arm, Havlir reported at a press briefing at the annual Conference on Retroviruses and Opportunistic Infections.

"These data support current WHO guideline-recommended treatment regimens for pregnant and breastfeeding women at all CD4-positive levels," she told MedPage Today. "This study provides reassurance that high levels of viral suppression are achievable."

The researchers also noted that the study demonstrated that infants have a low risk of HIV acquisition with these regimens, and that women can successfully initiate antiretroviral therapy when they present to the antenatal clinic, and can maintain therapy thereafter.

With the exception of the time point at delivery, viral suppression for both groups of women was high, and about the same antenatal and postpartum.

Grade I/II gastrointestinal adverse events were more frequent with lopinavir, but there were no differences in numbers of Grade III/IV adverse events.

The women on the lopinavir combo increased their CD4-positive cell counts more than those on efavirenz-based therapy, but that difference did not appear to influence clinical outcomes in the study. At delivery, women on lopinavir had a 57 CD4-positive cells/mm3 improvement, while those women on efavirenz had a 7 cells/mm3 decrease (P = 0.002). At 24 weeks postpartum, women on lopinavir had increased CD4-positivity by 179 cells/mm3 compared with a 109 cells/mm3 for women on efavirenz (P <0.01).

WHO Stage 4 clinical events were rare, the researchers said. Kaposi's sarcoma was observed in one woman randomized to efavirenz; pulmonary tuberculosis was diagnosed in one woman randomized to lopinavir. The only maternal death in the study was a motor vehicle accident in a woman on lopinavir. There were no differences in preterm birth, spontaneous abortion, stillbirth or neonatal death between study arms, the researchers said. Women in both arms reported high rates of adherence.

The PROMOTE (Pregnant Women and Infants Trial) enrolled HIV-infected antiretroviral-naïve pregnant women of 12-28 weeks' gestation. The women were stratified by gravidity and gestational age. They were assigned to either efavirenz plus zidovudine and lamivudine or to lopinavir boosted with ritonavir and the same nucleoside reverse transcriptase inhibitors. The infants received zidovudine or nevirapine. Women were counseled to breastfeed for 1 year after delivery.

The research team screened 593 women and assigned 195 to efavirenz and 194 to lopinavir. The average age of the women was 29; 90% of the women had more than one child; 67% had three or more children living at home.

In commenting on the study, press conference moderator Elaine Abrams, MD, professor of epidemiology at Columbia University in New York City, told MedPage Today, "I don't think this trial will change clinical practice. WHO recommends the efavirenz regimen – the same treatment for nonpregnant women and adults. They are all treated the same."

However, "we didn't have efficacy data before this study," she continued. "They have demonstrated that this regimen is quite good. It works well and it's safe and helps us be more comfortable with these recommendations."

In the U.S., lopinavir-based treatment is a recommended treatment in pregnancy, Abrams said. "It is a second-line treatment overseas, where it has never been recommended as a first-time therapy," she said.

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